Bostomatic 1000 Spindle Repair

The Bostomatic 1000 is a CNC vertical machining center that comes with 5-axis capabilities.  The spindle in this machine is coupling driven and grease lubricated.

CHALLENGE

When this Bostomatic 1000 spindle arrived at Northland Tool and Electronics we performed a breakdown and evlauation.  Upon inspection, we noted that the shaft was heavily rusted in the taper and ID, it was filled with leaves and cobwebs incoming. All four bearings in the spindle were contaminated.  The pulley surface has been GPG’d previously and the chrome had a gouge.  The rear threads were also folded over.  We then measured critical dimensions of the spindle a found two issues to address.  First the taper runout and front shoulder runout were both high (10µ).  Second, the front and rear shaft journals were undersized.  The front was -4/-5µ and the rear was -5/-6µ (ISO is ± 3.5).

SOLUTION

The following actions were performed on this Bostomatic 1000 spindle:

• Grind, chrome plate, and finish grind (GPG) the 40 taper and both front and rear shaft journals
• Replace bearings, o-rings, and assembly screws

RESULT

After reassembly of all components, adjusting bearing preload, and undergoing break-in and testing procedures, this spindle passed our final quality inspection before being returned to our customer with a 1-year warranty.